The present invention relates to an inkjet printing method using a porous ink jet recording element.
In a typical ink jet recording or printing system, ink droplets are ejected from a nozzle at high speed towards a recording element or medium to produce an image on the medium. The ink droplets, or recording liquid, generally comprise a recording agent, such as a dye or pigment, and a large amount of solvent. The solvent, or carrier liquid, typically is made up of water and an organic material such as a monohydric alcohol, a polyhydric alcohol or mixtures thereof.
An ink jet recording element typically comprises a support having on at least one surface thereof an ink-receiving or image-receiving layer, and includes those intended for reflection viewing, which have an opaque support, and those intended for viewing by transmitted light, which have a transparent support.
An important characteristic of ink jet recording elements is their need to dry quickly after printing. To this end, porous recording elements have been developed which provide nearly instantaneous drying as long as they have sufficient thickness and pore volume to effectively contain the liquid ink. For example, a porous recording element can be manufactured by cast coating, in which a particulate-containing coating is applied to a support and is dried in contact with a polished smooth surface.
Inkjet prints, prepared by printing onto inkjet recording elements, are subject to environmental degradation. They are especially vulnerable to damage resulting from contact with water and atmospheric gases such as ozone. The damage resulting from the post imaging contact with water can take the form of water spots resulting from deglossing of the top coat, dye smearing due to unwanted dye diffusion, and even gross dissolution of the image recording layer. Ozone bleaches inkjet dyes resulting in loss of density. To overcome these deficiencies ink jet prints are often laminated. Lamination is however expensive as it requires a separate roll of material. Alternatively inkjet recording elements having a two-layer construction have been employed. These elements typically have a porous ink-transporting topcoat of thermally fusible particles residing on either a swellable or porous ink-retaining layer. Upon printing the ink passes through the topcoat and into an ink-retaining layer. The topcoat layer is then sealed to afford a water and stain resistant print. Such topcoats containing thermally fusible particles typically either, contain a binder or are thermally sintered to provide a level of mechanical integrity to the layer prior to the imaging and fusing steps.
Print protection can also be provided by coating a polymer solution or dispersion on the surface of an inkjet media after image is formed. The aqueous coating solutions are often polymer dispersions capable of film-formation when water is removed.
EP 0858905 A1 relates to the preparation of a recording medium comprising a porous outermost layer by coating and drying a particulate thermoplastic resin above its glass transition temperature (Tg), but below its minimum film formation temperature (MFFT). There is a problem with the element in that the drying temperature has to be controlled very precisely between the Tg and MFFT in order to achieve the desired result. If the drying temperature is below the Tg, then a powdery layer is formed. If the drying temperature is above MFFT, then a complete coalesced film is formed which will not transport ink.
It is an object of this invention to provide an inkjet printing method using a porous ink jet recording element that, when printed with an ink jet ink, provides an image which has good quality and is water and abrasion resistant. It is another object of the invention to provide an ink jet printing method using a porous ink jet recording element, which is easy to manufacture and is flexible after printing and fusing to provide resistance to cracking.
These and other objects are achieved in accordance with the invention which comprises an ink jet printing method, comprising the steps of:
A) providing an ink jet printer that is responsive to digital data signals;
B) loading the printer with an inkjet recording element comprising a support having thereon a fusible, porous, image-receiving layer comprising non-porous polymeric particles having a core/shell structure comprising a polymeric, hydrophobic core covered with a polymeric, hydrophobic shell, the Tg of the polymeric, hydrophobic core being at least about 25xc2x0 C. higher than the Tg of the polymeric, hydrophobic shell;
C) loading the printer with an ink jet ink composition comprising water, a humectant, and a water-soluble dye; and
D) printing on the overcoat layer using the ink jet ink in response to the digital data signals.
By use of the printing method of the invention, a porous ink jet recording element is obtained that, when printed with an ink jet ink, has good abrasion and water-resistance, and is flexible after printing and fusing to provide resistance to cracking.